Chipping hammer tool retainer



Aug. 30, 1955 H. R. FISCHER 2,716,393

CHIPPING HAMMER TOOL RETAINER Original Filed March 17, 1949 INVENTOR.

H0 WHRD R. FISCHER United States Patent CHIPPING HAMMER TOOL RETAINER Howard R. Fischer, Detroit, Mich., assignor to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Original application March 17, 1949, Serial No. 81,935, now Patent No. 2,672,129, dated March 16, 1954. girdled and this application July 10, 1953, Serial No.

1 Claim. (Cl. 121-32) This invention relates to a chipping hammer and more particularly to a tool retainer for a chipping hammer.

It is the object of this invention to provide a simple chisel retaining device for chipping hammers which permits the easy removal of the chisel and makes the changing of chisels a simple, easy operation, and whereby when the chisels are in place they are positively retained against outward movement from the hammer casing.

For a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing, in which:

Fig. 1 is a perspective view of a tool embodying the principles of the invention and showing a chisel in position in the front end of the tool.

Fig. 2 is a fragmentary sectional view of the nose end of the tool taken on line 2-2 of Fig. 1.

Fig. 3 is a transverse sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a transverse sectional view similar to Fig. 3, but with the retaining plug having been turned to expand the retaining spring and to free the plug of the chisel element for the release of the same.

Fig. 5 is a longitudinal sectional view taken on line 5--5 of Fig. 4.

Referring now to the figures, the chipping hammer of the present invention comprises generally an outer casing 21 having an integral nose end portion 22 adapted to receive a chisel 23 within its opening 24. This chisel 23 is held within the opening 24 by a quick release key plug 25. The outer casing 21 is adapted to receive a cylinder head 28 having a throttle valve element 29 adapted to be depressed by a manually-operable lever 31 pivotally connected to the cylinder head 28.

Fitted within the outer casing 21 is a cylinder sleeve 35 having a hammer piston slideable therein. This hammer piston has a projection 37 adapted to tap the end of the chisel 23 which has been extended into the nose end portion 22 of the outer casing 21. The hammer piston can be made to deliver either fast blows upon the chisel 23 or slow taps.

The chisel 23 is generally of square section relieved at its corners, at the portion thereof adapted to fit the opening 24. This portion of the chisel is indicated at 103 and intermediate the length of this portion is a slot 104 adapted to receive the retaining plug 25. This retaining plug is round and has a tapered projection 105 adapted to enter the chisel slot 104 and a shoulder 106 adapted to engage with a shoulder 107 of plug opening 108 in the nose end 22 of the casing 21. The retaining plug 25 is held in place with the projection 105 in the slot 104 of the chisel element by a split spring ring 109 adapted to fill an annular recess 110 on the exterior of the nose portion 22. The ends of the ring terminate against a handle portion 111 of the retainer element. ,On the retainer element below the handle portion is a cam surface 112 adapted to act upon the ends of the spring ring 109 to expand them and to cause the retainer element to be lifted within the opening 108 and to thereby release the chisel element from its opening 24. The retaining plug 25 is merely turned ninety. degrees in order to release the chisel element. Upon the retaining plug being released from spring 109, it will be returned to its lowered position in the chisel slot under the action of the ends of the spring upon the cam surface 112 of the retainer element. The slot 104 in the chisel element is sutficiently long to permit the axial displacement of the chisel resulting from the hammering action.

While various changes may be made in the detail construction, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claim.

This application is a division of parent application Serial No. 81,935, filed March 17, 1949, which issued as Patent No. 2,672,129, on March 16, 1954. A copending divisional application Serial No. 429,209, filed May 12, 1954, contains claims to the distributing valve arrangement shown in said parent application.

What is claimed is:

In a chipping hammer having a nose portion with a tool opening for reception of a shank end of a chisel element, a chisel element retaining means including a key plug which is radially positioned in the nose portion and arranged for rotative and axial movement, and a split spring retaining ring arranged within a groove formed on the outer periphery of the nose portion, said key plug having camming surfaces adapted to be engaged by the ends of the retaining ring and arranged so that in a first position the key plug is forced radially inward by action of the retaining ring upon the camming surfaces whereby the inner end of the key plug will project into the tool opening, and being further arranged so that when the key plug is rotated up to 90 from said first position the retaining ring will force the key plug radially outward whereby the inner end thereof will not project into the tool opening.

References Cited in the file of this patent UNITED STATES PATENTS 825,669 Leineweber July 10, 1906 1,007,295 Lane Oct. 31, 1911 2,156,510 Nelson May 2, 1939 

